Multicast technologies play an increasingly significant role in the present internet. An interactive personality television (IPTV), a net-meeting, a live broadcast and the like all use the multicast technologies.
However, with the development of technology, the present development direction tends to not run conventional multicast protocols (i.e., the existing multicast protocols including a protocol Independent Multicast (PIM), an internet Control Message Protocol (IGMP), a multicast listener discovery protocol (MLD) and the like) in a backbone network, but relies on other technologies to implement a transmission of multicast traffic. Technologies that are commonly used include a bit indexed explicit replication (BIER) technology and the like.
The BIER technology is used for multicast forwarding, multicast states of intermediate nodes in a network are removed, and the multicasting forwarding can be performed only according to a BIER bit string to reach corresponding destination nodes. Thus, a control of the network is greatly simplified.
However, in a layer 2 network, since there is no effective means for advertising bit string length support information of each forwarding node, error handling may occur during the multicast forwarding, and even traffic may be lost.